Can the water in the toilet go back into the pipe?

Adding a check valve to the water outlet means that the water can only come out, not pour it back

This is a perverted practice of certain companies or certain countries. >>>More

The blue water that flows back into the water pipe in the toilet bowl is the blue toilet block that melts in the toilet tank. The main reason for the backflow of water in the toilet tank is the backflow of water in the toilet tank through the tap due to a change in the pressure of the water pipe or a damaged fill valve. >>>More

It is better not to pour it, you can flush the toilet, but do not pour it into the tank, after all, it is bath water.

Close the water pipe, unscrew the riser connected to the outer water pipe, and check that it can be taken out of the toilet. Remove the hydrator, see that there is a small square column in the middle of the inner tube, and pull it out with needle-nose pliers.